Supporting member for a seat and back of a chair

ABSTRACT

A supporting member for a seat and a back of a chair includes a main body, a pivotal base, and a resilient L-shaped connecting part. The main body is connected to a bottom side of the seat, and a support base on top of a support rod of the chair. The pivotal base is pivoted to the support base from front projecting end portions, and connected to the main body from an intermediate portion by means of an inverted U-shaped support part passed through a pair of slots of the main body. The L-shaped connecting part is connected to the pivotal base from a lower part, and to the back from an upper part such that the back can be pushed back with an enlarged space between same and the seat on a sitter&#39;s leaning back.

BACKGROUND OF THE INVENTION

[0001] The present invention relates to a supporting member of a seat and back of a chair, and particularly to one of a seat and back of an office chair, which permits a space between the seat and the back to become bigger when the sitter leans against the back for the sitter to sit on the chair comfortably.

[0002] Referring to FIGS. 6 and 7, a conventional supporting member for a seat and back of an office chair includes a butterfly-shaped main body 5, a support base 6 and a support rod 61.

[0003] The butterfly-shaped main body 5 is fixed to a bottom side of a seat 7, which is connected to a back 71 from a rear edge; screws are screwed into through holes 52 and the seat to fix the main body 5 to the seat 7. The main body 5 further has side plate parts 53 projecting downwards from the bottom.

[0004] The support base 6 has two side plate parts projecting upwards, and is connected to a top end portion of the support rod 61. The main body 5 is pivoted to the support base projecting side plate parts from the side plate parts 53. The control lever 62 is operationally associated with the support rod 61 such that both can control a height of the seat and back by means of a compressed air device.

[0005] A knob assembly 63 is associated with the support base 6, and the butterfly-shaped main body 5 with an elastic member biasing a front end portion of the main body 5 downwardly.

[0006] Thus, when a sitter leans against the back, the back will be pushed backwards to a sloping position, and at the same time, the seat will be pivoted on the support base 6 with a front end moving up; a space between the seat and the back will not change.

[0007] From the above description, the conventional chair can be found to have a disadvantage that the space between the seat and the back won't become bigger for a sitter to sit more comfortably when he leans back.

[0008] Another conventional supporting member for a seat and a back of a chair includes a butterfly-shaped main body fixed to the seat and a resilient L-shaped connecting member connecting the seat and the back; thus, when the sitter leans back, the space between the seat and back will become bigger. However, the seat won't change a position for a sitter to sit more comfortably when he leans back.

SUMMARY OF THE INVENTION

[0009] Therefore, it is a main object of the present invention to provide a support member for a seat and a back of a chair which permits a space between the seat and the back to become bigger, and permits the seat to be pivoted to a suitable position when a sitter leans back for a sitter to sit comfortably.

[0010] The supporting member of the present invention includes a main body, a pivotal base, and a resilient L-shaped connecting part. The main body is fixedly connected to a bottom side of the seat and pivoted to a support base on a top end of a support rod of the chair. The main body has two side plates projecting down from a bottom side.

[0011] The pivotal base is pivoted to the support base from front projecting end portions of two side plates, and connected to an inverted U-shaped supporting part passed through two slots of the main body; the inverted U-shaped supporting part has a flat upper part fitted onto a recessed portion of the main body.

[0012] The resilient L-shaped connecting part is connected to the pivoted base from a lower part, and to the chair back from an upper part. Thus, the back can be pushed to enlarge a space between the back and the seat when a sitter leans back.

BRIEF DESCRIPTION OF THE DRAWINGS

[0013] This invention will be better understood by referring to the accompanying drawings, wherein:

[0014]FIG. 1 is an exploded perspective view of the supporting member for a seat and back of a chair according to the present invention.

[0015]FIG. 2 is a side view of the supporting member for a seat and back of a chair in FIG. 1.

[0016]FIG. 3 is a cross-sectional view of the supporting member for a seat and back of a chair in FIG. 1.

[0017]FIG. 4 is a side view of a chair with the supporting member of the present invention.

[0018]FIG. 5 is a side view of a chair with the supporting member of the present invention, the back being pushed back with a space between same and the seat being enlarged.

[0019]FIG. 6 is an exploded view of a conventional supporting member for a seat and back of a chair.

[0020]FIG. 7 is a side view of a chair with the supporting member in FIG. 6.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0021] Referring to FIGS. 1 and 2, a supporting member for a seat and a back of an office chair in the present invention includes a main body 1, an inverted U-shaped supporting part 2, a pivotal base 3, an L-shaped connecting member 4, a support base 6 and a support rod 61.

[0022] The main body 1 substantially has a butterfly shape, and has a recessed portion 11, slots 12 on two ends of the recessed portion 11, a top part 13, and two side plates 15 projecting down from a bottom side. The side plates 15 have pivotal holes 16.

[0023] The inverted U-shaped supporting part 2 has a flat upper part 22, and two side parts 21 each having a hole 23. The inverted U-shaped is movably connected to the main body 1 with the side parts 21 each passed through a respective one of the slots 12 of the main body 1.

[0024] The main body 1 is coupled to a bottom side of the seat by means of screws (not shown) screwed through holes 14 of the main body 1, and into the seat bottom.

[0025] The support base 6 is connected to an upper end portion of the support rod, and has two side plate parts having first pivotal holes 66, and second pivoted holes 64. The main body 1 is pivoted to the support base 6 by means of a pin passed through the first pivotal holes 66 of the support base 6 and the holes 16 of the main body 1. The control lever 62 is operationally associated with the support rod 61 such that same can control a height of the seat by means of a compressed air device in the support rod 61. The compressed air device is not the subject of the present invention. So, it is not described in details here.

[0026] The pivotal base 3 has a lower part 31, an elongated hole 32 on the lower part 31, and two side plates 33 projecting on two sides of the lower part 31; the side plates 33 each has a projecting end portion 37 having a pivotal hole 38. The side plates 33 each further has a confining protrusion 34 and a hole 35. The pivotal base 3 is pivoted to the second pivotal holes 64 of the support base 6 from the pivotal holes 38 by means of a pivotal pin 39, and is connected to the inverted U-shaped supporting part 2 by means of a connecting pin 36 passed through the holes 35 and the holes 23.

[0027] The L-shaped connecting member 4 is resilient, and has a lower part 41 connected to the elongated hole 32 of the pivotal base 3; a knob 43 is screwed through the elongated hole 32 and the lower part 41, and connected to a nut 42. The confining protrusions 34 of the pivotal base 3 prevent the L-shaped connecting member 4 from falling off. Thus, a position of the L-shaped connecting member 4 relative to the pivotal base 3 can be adjusted. An upper part of the L-shaped connecting member 4 is fixedly connected to the back of the chair.

[0028] A knob assembly 63 is associated with the support base 6, and the main body 1 with an elastic member of the knob assembly 63, biasing a front end portion of the main body 1 down. When a sitter leans against the back of the chair, the back will be pushed to a sloping position with the pivotal base 3, the inverted U-shaped supporting part 2, the rear part of the seat associated with the main body 1 moving down. Thus, the rear upper part of the side plate parts of the support base 6 will contact the bottom side of the main body 1. And, the space between the seat and the back become bigger as shown in FIG. 5.

[0029] From the above description, the supporting member for a seat and a back of a chair of the present invention can be known to have desirable features as follows:

[0030] 1. When a sitter leans back, the space between the seat and the back can become bigger for him/her to feel comfortable.

[0031] 2. The butterfly-shaped main body can also be used on a conventional supporting member for a seat and back of a chair.

[0032] 3. The position of the L-shaped connecting member 4 can be adjusted for permitting the user to get a suitable space between the seat and the back. 

What is claimed is:
 1. A supporting member for a seat and a back of a chair comprising a main body fixedly connected to a bottom side of said seat, and pivoted to a support base on a top end of a support rod of said chair; said main body having two side plates projecting down from a bottom side; a pivotal base pivoted to said support base from front projecting end portions of two side plates, and connected to an inverted U-shaped supporting part passed through two slots of said main body; a resilient L-shaped connecting part connected to said chair back from an upper part; said L-shaped connecting part being connected to said pivotal base from a lower part for permitting said back to be pushed to a sloping position with a substantially enlarged space between said back and said seat on a sitter's leaning back.
 2. The supporting member for a seat and a back of a chair as claimed in claim 1, wherein said pivotal base is connected to said inverted U-shaped supporting part by means of a pin passed through lower portions of said inverted U-shaped supporting part, and said side plates thereof.
 3. The supporting member for a seat and a back of a chair as claimed in claim 1, wherein said main body has recessed portions between said slots, and said inverted U-shaped supporting part has a flat upper part fitted onto said recessed portion when same is passed through said slots.
 4. The supporting member for a seat and a back of a chair as claimed in claim 1, wherein said pivotal base has an elongated hole; said L-shaped connecting member being connected to said pivotal base by means of a knob screwed through said elongated hole and said lower part thereof for permitting a position of said back associated with said L-shaped connecting member to be adjusted.
 5. The supporting member for a seat and a back of a chair as claimed in claim 1, wherein said side plates of said pivotal base each has a confining protrusion on an inner side to detain said L-shaped connecting member lower part. 